Question aio makes a rattling noise in pwm mode

Aug 9, 2022
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i have a fractal s24+ aio and when i put it in pwm mode it makes a rattling noise but when i put it in auto mode the noise disappears. Are there air bubbles in the pump or is my aio faulty
note* when its in pwm mode the pump spins at around 2700 rpm and in auto mode around 800 rpm


 

Lutfij

Titan
Moderator
Welcome to the forums, newcomer!

We're going to need more context. Can you include an image of the AIO's mounting to the case in your build? Which header is the AIO plugged into on your motherboard? Speaking of motherboard, what is the model for your Asus motherboard? BIOS version for said motherboard?
 
Reactions: CompuGuy71

Paperdoc

Polypheme
Ambassador
Your post raises an intriguing question. You say, "in pwm mode the pump spins at around 2700 rpm and in auto mode around 800 rpm ". That strongly suggests that the FANS are of the 3-pin design. On each fan there will be TWO cables. One ends in a smaller connector about 3/8" wide with two ridges running down one side and this plugs into a fan header. The other has a wider connector and looks like it had 4 holes but one is plugged; this goes to a LIGHTING header somewhere. I am talking about the SMALLER fan MOTOR connector. Does it have THREE holes, or 4?

A three-pin fan connected to a header using the newer PWM Mode of control will always run full speed. Modern mobos use headers that can do that OR the older Voltage Control Mode (aka DC Mode) which CAN control the speed of a 3-pin fan. Such headers often have a "Auto" option to test what fan design has been plugged in and select the correct Mode. Your description sounds a LOT like a 3-pin fan: when you set the header to PWM Mode it runs full speed, but in Auto mode it selects the correct DC Mode. and runs at proper speed. HOWEVER, the web pages for that AIO system SAY it is supplied with PWM-style fans with FOUR holes in the fan motor connector. So which do you really have?
 
Reactions: CompuGuy71
Aug 9, 2022
3
0
10
0
Welcome to the forums, newcomer!

We're going to need more context. Can you include an image of the AIO's mounting to the case in your build? Which header is the AIO plugged into on your motherboard? Speaking of motherboard, what is the model for your Asus motherboard? BIOS version for said motherboard?
the motherboard is the asus rog b550-f-gaming. bios version is american megatrends inc. 2407
the cable from the pump i have connected to aio_pump mark on the motherboard


View: https://imgur.com/a/RkwrByG

View: https://imgur.com/a/Qgd4i6I
 

Paperdoc

Polypheme
Ambassador
I'm sorry, I made an error in my previous posting. I spoke of how 3- and 4-pin FANS operate, and said your first post sounded like a 3-pin fan on a header with certain settings. In fact, your first post said the PUMP is the item whose speed you were quoting. THAT makes more sense.

On most AIO systems the PUMP is designed to run at full speed all the time. Control of CPU cooling is done solely by changing the speeds of the FANS on the rad. For this to work, the PUMP needs to be connected to a header that always supplies a full 12 VDC to it, whereas the FANS need to be plugged into a header that WILL control their speeds (in PWM Mode for a 4-pin rad fan) AND bases that control on the temperature measured inside the CPU chip by its built-in sensor. Normally that is the CPU_FAN or CPU_OPT header, and you have both, OP.

Your PUMP unit uses a "trick" common on many. It is wired just like a 3-pin fan. So when you plug it into a header operating in PWM Mode, it always runs full speed, exactly what you want. You have it plugged into the AIO_PUMP header, which is a great place. IF you set that header to PWM Mode it will operate always full speed as it is supposed to. But IF you set that header to "AUTO", it will test the item plugged in at every start-up by using PWM Mode signals to try to slow it down. If that does not work, (and it does not for your pump) it assumes the "fan" must be the older DC Mode type and changes its operation to DC Mode so it CAN slow down the Pump. That is exactly what the AIO designers did NOT want! You SHOULD set that AIO_PUMP header to PWM Mode.

Now, THAT is what gives you your original problem - noise when it runs full speed. That is NOT normal for that pump. Two items could cause that - air trapped in the pump is one. You can try to move it out of there. With your system running, pick up the whole case and turn it slowly to various angles to try to get the air inside the pump to a pump exit point so it can flow onwards to another place like the rad. If that doees not work you can contact the makers of the AIO system - their Tech Support people - and ask for their advice. MAYBE the pump actually is faulty, but trapped air is a common cause of this.
 
Aug 9, 2022
3
0
10
0
I'm sorry, I made an error in my previous posting. I spoke of how 3- and 4-pin FANS operate, and said your first post sounded like a 3-pin fan on a header with certain settings. In fact, your first post said the PUMP is the item whose speed you were quoting. THAT makes more sense.

On most AIO systems the PUMP is designed to run at full speed all the time. Control of CPU cooling is done solely by changing the speeds of the FANS on the rad. For this to work, the PUMP needs to be connected to a header that always supplies a full 12 VDC to it, whereas the FANS need to be plugged into a header that WILL control their speeds (in PWM Mode for a 4-pin rad fan) AND bases that control on the temperature measured inside the CPU chip by its built-in sensor. Normally that is the CPU_FAN or CPU_OPT header, and you have both, OP.

Your PUMP unit uses a "trick" common on many. It is wired just like a 3-pin fan. So when you plug it into a header operating in PWM Mode, it always runs full speed, exactly what you want. You have it plugged into the AIO_PUMP header, which is a great place. IF you set that header to PWM Mode it will operate always full speed as it is supposed to. But IF you set that header to "AUTO", it will test the item plugged in at every start-up by using PWM Mode signals to try to slow it down. If that does not work, (and it does not for your pump) it assumes the "fan" must be the older DC Mode type and changes its operation to DC Mode so it CAN slow down the Pump. That is exactly what the AIO designers did NOT want! You SHOULD set that AIO_PUMP header to PWM Mode.

Now, THAT is what gives you your original problem - noise when it runs full speed. That is NOT normal for that pump. Two items could cause that - air trapped in the pump is one. You can try to move it out of there. With your system running, pick up the whole case and turn it slowly to various angles to try to get the air inside the pump to a pump exit point so it can flow onwards to another place like the rad. If that doees not work you can contact the makers of the AIO system - their Tech Support people - and ask for their advice. MAYBE the pump actually is faulty, but trapped air is a common cause of this.
i have changed the aio_pump settings in the bios from disabled to pwm mode and it seems that it running on 100% has been fixed (thank you)
as for the noise problem i will look into if its air bubbles or a faulty aio
 

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